The present invention relates generally to semiconductor manufacturing, and more particularly, to systems, methods and apparatus for performing ion milling operations in a plasma etch chamber.
Etching many materials often form non-volatile etch process byproducts. By way of example, etching the film stacks of materials to form features in magnetic random access memory (MRAM) and resistive random access memory (RRAM) structures and devices. The non-volatile etch process byproducts can form deposits on the sidewalls of the features. The sidewall deposits cause device malformation such as shortening the active device and other malformations.
Ion milling is used to remove non-volatile etch process byproduct deposits on the sidewalls of the features etched in various non-volatile material layers. Ion milling directs ions at the sidewalls of the features to remove the etch byproduct deposits.
Typical ion milling is ineffective as feature sizes become smaller than 200 nm in width and/or the feature depth to width (aspect) ratio exceeds 1:1. Thus, what is needed is an ion milling process that is effective in feature sizes smaller than 200 nm in width and/or feature aspect ratio exceeds 1:1.